Mobile heavy construction equipment such as tractor backhoes, front loader tractors, excavators, and skid steer loaders commonly are equipped with an hydraulic power system which is capable of supplying power to various hydraulically powered auxiliary implements. In practice, the dirt scooping or dirt moving bucket of a tractor backhoe or excavator may be removed from such tractor backhoe's or excavator's boom arm. Similarly, the lift bucket of a skid steer loader or of a front loader tractor commonly is removable. In place of such dirt working buckets, various auxiliary hydraulically powered implements may be mounted.
Among such auxiliary hydraulically powered implements are implements which rotatably drive wood chipping wheels, blades, drums or discs; implements which rotatably drive concrete cutting wheels, blades, drums or discs; implements which rotatably drive grinding wheels, blades, drums or discs; implements which rotatably drive milling wheels, blades, drums or discs; implements which rotatably drive planing wheels, blades, drums or discs; or implements which rotatably drive tined earth tillers. Such implements, when mounted upon the boom arm, or lift arms, as the case may be, of a tractor backhoe, excavator, front loader tractor, or skid steer loader, are rotatably driven for operative engagement of a surface such as a tree stump, a paved road, and various ground surfaces. In any such application, it is desireable to apply to the implement means for controlling the depth at which the implement engages the surface.
A known depth control means includes an hydraulic ram or a plurality of hydraulic rams installed as a mechanical linkage for selectively raising and lowering the rotatable member with respect to the elevation of the surface to be engaged. Commonly, such hydraulic rams bias between the rotatable member and a frame which rollably or slidably moves along the surface. Also, commonly, such hydraulic rams are configured to bias between a mounting plate attached to the boom arm or lift arms, as the case may be, and a cantilevered support arm which suspends the rotatable member. A problem associated with utilizing such hydraulic rams for depth control is that hydraulic rams are expensive and troublesome to install and maintain, such hydraulic rams are subject to excessive wear and breakage, and such hydraulic rams necessitate an additional hydraulic control which is cumbersome for heavy equipment operators to manipulate.
The instant invention provides a solution to the problems outlined above by eliminating depth control by means of installation of additional hydraulic rams; utilizing a plurality of arms interlinking the mounting plate and the rotatable implement, such arms being adapted for converting rotational motion of the mounting plate to alternate upward and downward motion of the rotatable implement